茶多酚抗过敏作用的研究

目的：研究茶多酚（ＴＰ）的抗过敏作用。方法：利用小鼠被动性皮肤过敏反应（ＰＣＡ）实验、组织胺引起正常豚鼠离体回肠收缩试验、豚鼠ＳｃｈｕｌｔｚＤａｌｅ回肠收缩反应以及测定过敏豚鼠肺脏ＳＲＳＡ含量等方法。结果：茶多酚能明显抑制小鼠被动性皮肤过敏反应、组胺所引起的回肠平滑肌收缩而使组胺收缩曲线右移,并抑制豚鼠ＳｃｈｕｌｔｚＤａｌｅ反应的回肠收缩以及致敏豚鼠肺组织中ＳＲＳＡ的释放。结论：茶多酚的抗过敏作用可能与抗组胺及抑制慢反应物质（ＳＲＳＡ）生成有关     

茶树油的提取工艺优化试验研究

目的:以茶树油提取率为考察指标,研究茶树油的提取工艺.方法:采用正交试验进行优选,气相色谱法测定4-羟基萜烯含量.结果:影响茶树油提取率的主要因素是提取时间,对茶树油的提取有显著影响;其次是加水量,对茶树油的提取有较大影响;浸泡时间的影响最小.各因素对4-羟基萜烯含量无影响.结论:最佳的提取工艺为浸泡时间2 h,提取时间6 h,加水800 ml.     

金银花多酚类物质的纯化研究

目的考察常用的大孔吸附树脂对金银花多酚类物质的纯化效果,筛选纯化工艺条件。方法以总酚的质量分数和回收率作为指标,采用静态吸附及动态吸附考察树脂的吸附、解吸性能。结果 NKA-2型树脂对多酚类物质的吸附能力明显强于其他树脂,其载药量为7倍树脂体积,水洗5倍树脂体积,60%乙醇洗6倍树脂体积。此条件下,浸膏量减少40%左右,总酚质量分数提升近一倍,达到60%左右,样品回收率达到55%。结论 NKA-2型树脂对金银花多酚类的纯化效果较好,适用于金银花多酚类物质的分离纯化。     

Cancer chemoprevention by tea polyphenols through modulating signal transduction pathways

The action mechanisms of several chemopreventive agents derived from herbal medicine and edible plants have become attractive issues in cancer research. Tea is the most widely consumed beverage worldwide. Recently, the cancer chemopreventive actions of tea have been intensively investigated. It have been demonstrated that the active principles of tea were attributed to their tea polyphenols. Recently, tremendous progress has been made in elucidating the molecular mechanisms of cancer chemoprevention by tea and tea polyphenols. The suppression of various tumor biomarkers including growth factor receptor tyrosine kinases, cytokine receptor kinases, PI3K, phosphatases, ras, raf, MAPK cascades, N x FB, I x B kinase, PKA, PKB, PKC, c-jun, c-fos, c-myc, cdks, cyclins, and related transducing proteins by tea polyphenols has been studied in our laboratory and others. The I x B kinase (IKK) activity in LPS-activated murine macrophages (RAW 264.7 cells) was found to be inhibited by various tea polyphenols including (-) epigallocatechin-3-gallate (EGCG), theaflavin (TF-1), theaflavin-3-gallate (TF-2) and theaflavin-3,3'-digallate (TF-3). TF-3 inhibited IKK activity in activated macrophages more strongly than did the other tea polyphenols. TF-3 inhibited both IKK1 and IKK2 activity and prevented the degradation of I x B x and I x B x in activated macrophage cells. The results suggested that the inhibition of IKK activity by TF-3 and other tea polyphenols could occur by a direct effect on IKKs or on upstream events in the signal transduction pathway. TF-3 and other tea polyphenols blocked phosphorylation of IB from the cytosolic fraction, inhibited NFB activity and inhibited increases in inducible nitric oxide synthase levels in activated macrophage. TF-3 and other tea polyphenols also inhibited strongly the activities of xanthine oxidase, cyclooxygenase, EGF-receptor tyrosine kinase and protein kinase C. These results suggest that TF-3 and other tea polyphenols may exert their cancer chemoprevention through suppressing tumor promotion and inflammation by blocking signal transduction. The mechanisms of this inhibition may be due to the blockade of the mitogenic and differentiating signals through modulating EGFR function, MAPK cascades, NFkappaB activation as well as c-myc, c-jun and c-fos expression.     

Pharmacological effects of green tea on the gastrointestinal system

Green tea is rich in polyphenolic compounds, with catechins as its major component. Studies have shown that catechins possess diverse pharmacological properties that include anti-oxidative, anti-inflammatory, anti-carcinogenic, anti-arteriosclerotic and anti-bacterial effects. In the gastrointestinal tract, green tea was found to activate intracellular antioxidants, inhibit procarcinogen formation, suppress angiogenesis and cancer cell proliferation. Studies on the preventive effect of green tea in esophageal cancer have produced inconsistent results; however, inverse relationships of tea consumption with cancers of the stomach and colon have been widely reported. Green tea is effective to prevent dental caries and reduce cholesterols and lipids absorption in the gastrointestinal tract, thus benefits subjects with cardiovascular disorders. As tea catechins are well absorbed in the gastrointestinal tract and they interact synergistically in their disease-modifying actions, thus drinking unfractionated green tea is the most simple and beneficial way to prevent gastrointestinal disorders.     

茶多酚对内毒素抑制人牙周膜成纤维细胞增殖的影响

目的 观察茶多酚对脂多糖(LPS)诱导下人牙周膜成纤维细胞(HPDLFs)增殖的影响.方法 采用组织块培养法培养原代HPDLFs并传代、免疫组化检测,取第5代细胞用于实验.将LPS及茶多酚分组,采用四甲基偶氮唑盐(MTT)法分别于24、48、72 h检测HPDLFs增殖活力.结果 免疫组化染色结果显示,所培养细胞的波形丝蛋白染色呈阳性表现,阳性部位位于胞质,角蛋白染色呈阴性表现.各浓度LPS组在24、48、72 h的光密度(OD)值(4 mg/L LPS组:0.323±0.007、0.345±0.010、0.437±0.007;20 mg/L LPS组:0.270±0.004、0.283±0.009、0.367±0.007; 100 mg/L LPS组:0.175±0.006、0.187±0.006、0.248±0.005;500 mg/L LPS组:0.088±0.004、0.091±0.006、0.153±0.009)与同时段空白对照组(0.306±0.008、0.333±0.007、0.399±0.007)组间比较差异均有统计学意义(均P＜0.05).100 mg/L LPS组和各浓度茶多酚组在24、48、72 h的OD值(100 mg/L LPS组:0.216±0.010、0.260±0.010、0.352±0.012; 100 mg/L LPS组+0.125 g/L茶多酚组:0.300±0.010、0.408±0.013、0.490±0.014;100 mg/L LPS组+0.25 g/L茶多酚组:0.333±0.012、0.416±0.010、0.532±0.012;100 mg/L LPS组+0.5 g/L茶多酚组:0.390±0.012、0.485±0.011、0.642±0.013;100 mg/L LPS组+1 g/L茶多酚组:0.368±0.010、0.481±0.006、0.621±0.007)与同时段空白对照组(0.450±0.012、0.528±0.011、0.687±0.010)组间比较,差异均有统计学意义(均P＜0.05);各浓度茶多酚组在24、48、72 h的OD值均低于同时段100 mg/L LPS组(均P＜0.05).结论 LPS抑制HPDLFs的增殖,茶多酚明显促进LPS诱导下HPDLFs的增殖,这提示茶多酚可应用于牙周炎的预防及治疗.     

茶多酚对家兔阳离子化牛血清白蛋白肾炎模型的治疗作用

目的 探讨茶多酚对家兔阳离子化牛血清白蛋白模型(C-BSA)肾炎的治疗作用. 方法 按文献方法复制家兔C-BSA肾小球肾炎模型,并用3种不同剂量的茶多酚 (30, 100 和 300 mg*kg-1) 给C-BSA肾小球肾炎模型兔灌胃,每日1次,连续 14 d. 结果 茶多酚不仅可以显著减少模型兔 24 h 尿蛋白分泌,降低血清肌酐和尿素氮水平,而且可以减轻肾小球病理损害,并且存在明显的量效关系. 结论 茶多酚对家兔C-BSA模型肾炎具有明显的治疗作用.     

Polyphenols and Their Role in Obesity Management: A Systematic Review of Randomized Clinical Trials

Polyphenols have been suggested to reduce body weight and modify body composition through different mechanisms. These effects have been extensively studied in animals and in vitro and to a lesser extent in humans. The aim of this review is to consider the association between polyphenols and body weight status by focusing on human intervention studies. We conducted a systematic literature search in MEDLINE (via EBSCOhost), ProQuest CENTRAL, and Cochrane CENTRAL without time restrictions. Randomized controlled trials assessing the effect of polyphenols on weight and/or body composition in the overweight and/or obese population were included. Nineteen studies met our inclusion criteria. Results suggest that further research is required before supporting a potential role of polyphenols in reducing weight in overweight and obese individuals (nine studies showed a significant decrease in weight by a mean of 1.47 ± 0.58 kg). Nevertheless, several studies indicated that polyphenols might be effective in preventing small increases in weight during periods of overfeeding rather than reducing weight as such. The outcomes noted do not yet support polyphenol supplementation as a complementary approach in weight loss diets. Further larger trials with a duration of 12 months or more are needed to elucidate the effect of polyphenols on body weight status. Copyright © 2017 John Wiley & Sons, Ltd.     

白藜芦醇诱导肿瘤细胞凋亡研究进展

白藜芦醇是一种具有抗氧化、抗肿瘤、诱导细胞凋亡等生物活性的天然多酚类化合物。本文对近年来白藜芦醇诱导人宫颈癌HeLa细胞、白血病细胞、肝癌细胞和胃癌细胞等细胞凋亡方面的研究进展进行了分析和总结,并重点探讨了白藜芦醇诱导肿瘤细胞凋亡的分子机制,总结了白藜芦醇通过阻滞细胞周期、调节相关基因及蛋白表达和线粒体诱导细胞凋亡途径的研究现状,以及白藜芦醇作为肿瘤药物在临床研究中的潜在应用前景。     

微波辅助提取鼠尾藻多酚及抗氧化活性研究

本文研究了微波辅助提取鼠尾藻多酚的工艺条件。探讨了微波功率、微波提取时间、料液比及乙醇的浓度对鼠尾藻多酚的提取率和纯度的影响。结果表明微波辅助提取优于超声辅助提取,微波提取最佳条件为：微波提取功率700w,乙醇浓度15%,液固比25（m l/g）,微波处理时间40 s。